The present invention relates to novel 2-fluoro-, 2,2-difluoro- and 2,2,2-trifluoroethoxy pyrimidine- and triazine-containing sulfonylureas which are useful as preemergent and postemergent herbicides.
Herbicidal benzenesulfonylureas of the formula ##STR1## wherein among the substituents disclosed R.sub.4-6 can each be hydrogen, R.sub.3 can be alkoxy of 1-4 carbon atoms, X can be alkoxy of 1-3 carbon atoms and Z is methyl or methoxy are disclosed in U.S. Pat. No. 4,127,405, issued Nov. 28, 1978 to Levitt.
European Patent Application (EP-A) No. 9419, published Apr. 2, 1980, discloses herbicidal benzene and thiophene sulfonylureas such as ##STR2## wherein among the substituents disclosed R.sub.4 can be OCH.sub.3, X can be OCH.sub.3, and Y can be OCH.sub.2 CF.sub.3.
South African Application No. 825671 (Swiss priority Aug. 6, 1981; EP-A-72,347, published Feb. 16, 1983) claims ortho-substituted alkoxy benzenesulfonylureas such as ##STR3##
South African patent application No. 835165 filed by Ciba-Geigy (Swiss Priority 7/16/82) discloses herbicidal sulfonylureas of the general structure shown below: ##STR4## wherein A is an unsubstituted or substituted bridge of 3 or 4 atoms which contains 1 or 2 oxygen, sulfur or nitrogen atoms and, together with the linking carbon atom, forms a non-aromatic 5- or 6-membered heterocyclic ring system, with the proviso that two oxygen atoms are separated by at least one carbon atom and that oxygen and sulfur atoms are only linked to each other if the sulfur atom takes the form of the --SO-- or SO.sub.2 -- group; and R.sub.3 and R.sub.4 may be, among other values, a C.sub.1 -C.sub.4 haloalkoxy group.